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Equine magnetic therapy: the positives and negatives

You want to believe. You really do. And there are many well-known horsemen, doctors, physicists and PhD's telling you that you should.

Dr. Robert Holcomb MD, PhD, at the Vanderbilt University Medical Center, writes, "Magnetic fields produce the following results when in direct contact with the body: increased circulation; vasodilatation; muscle relaxation; reduction of edema; reduction of nerve-cell firing (which reduces pain); and reduction of free radicals (which improves the body's ability to fight inflammation and improves the immune system).

Magnetic-therapy proponents rely on physics to validate their belief in the healing action of magnets and will take you through a discussion of Faraday's Law and the Hall effect. "The combination of the electromotive force, altered ionic pattern and the currents (caused by physical effects based on physics principles) causes blood-vessel dilation with a corresponding increase in blood flow," states Dr. M. Porter in a 1997 article in Equine Vet Data.

Your clients see advertisements for magnetic-therapy devices in all the popular equine magazines, and owners and trainers routinely give testimonials as to the varied beneficial effects that these units produce.

What could be better than to apply a magnetic joint wrap, footpad or body blanket and improve circulation, reduce inflammation and help your horse heal?

You'd really, really like to believe, but ...

Arguments pro and con

The problem is that there are equally many well-known scientists, clinicians and researchers on the other side of this issue.

David Ramey DVM, a California practitioner fast becoming the "Ralph Nader" of the profession, concludes, "There appear to be no published scientific studies available that demonstrate that any form of magnetic therapy is valuable in the treatment of disease conditions in the horse."

Dr. Phillip Steyn and a group of researchers in the Department of Radiological Health Services at the College of Veterinary Medicine at Colorado State University looked at the effects of static magnets on blood flow in the metacarpas of the horse and concluded, "static magnetic fields associated with the application of commercially available magnetic wraps for 48 hours did not increase the blood flow pattern of the metacarpas under the wrap."

Even though electromagnetic field therapy used for treatment of delayed and non-union fractures in humans is FDA-approved and supported by numerous studies, work by Dr. Bramlage, Dr. Collier and others failed to show similar usefulness in the horse. Other studies done in horses call the claims of "increased blood flow" and "pain reduction" following magnetic therapy into question.

But no sooner than you decide to discount this modality, a new study is published that makes you rethink your position — again.

Dr. Carlos Vallbona investigated the pain response in post-polio patients at the Baylor College of Medicine's Institute for Rehabilitative Research in Houston, Texas. In a double-blind study of 50 patients using magnets, a significant reduction in pain was reported by those patients using active magnets as opposed to patients using "sham" magnets. Twenty-nine of the patients with active magnets reported that, on average, they felt a reduction in pain from 9.6 to 4.4 (0 to 10 scale) while the 21 other patients using the sham magnets reported a reduction in pain of 9.5 to 8.4. This significant difference lends some "science" to the magnetic-therapy discussion.

Dr. William Jarvis, president of the National Counsel Against Health Fraud, previously was a detractor of magnetic therapy, calling it "essentially quackery." But after Dr. Vallbona"s findings were published, Dr. Jarvis tentatively admits that it (magnetic therapy) may have value.

Dr. Michael Weintraub and the magnetic-research group from the Department of Neurology at New York Medical College reported a randomized, double blind, placebo-controlled study looking at the reduction in diabetic-associated peripheral neuropathy achieved by wearing static magnetic shoe insoles.

These investigators concluded, "Although many questions remain about a precise mechanism of action, the present study provides convincing data confirming that the constant wearing of static, permanent, magnetic insoles produces statistically significant reduction of neuropathic pain." This study and others have led some veterinarians and owners to try magnetic footpads or magnetic bell boots as treatment for hoof-related pain.